Introducing: Dental Calculus

One possibility is to study human bones; human bones are found all over the world. But, the soft tissue, such as skin and organs are gone by the time we find them and the bones alone have only limited information on health, disease or diet. Another possibility is mummies, they still have soft tissue but are geographically limited and limited in time as well. A third option is to look at coprolites, which is fossilized human poop and incredibly interesting! You can learn a lot about human diet and your intestines by looking at them. But they too are very rare.

So what other material is out there?

It is dental calculus, or mineralized dental plaque. Since people in the past did not clean their teeth as well as we do now, we find big chunks on their teeth. So, their calculus has been preserved over time, is abundant and ubiquitous around the world at all time periods going back thousands of years.

But why do we in archaeology dig this calculus?

Well, that’s because what we can find inside it! Dental calculus is built up of several layers, forming a matrix. Everything that passes through your mouth may become entrapped in this matrix. Such as, food that you eat.Using the newest DNA technologies on dental calculus we found DNA belonging to food, such as plant DNA and DNA from animals. But, we have found more in dental calculus.

Looking at Health, Disease, and Diet

Using the same DNA technologies, we found microbes that are involved in caries formation and saw that these microbes did not have the antibiotic resistance genes that so many microbes nowadays have. We also found microbes that are known to be associated with the lungs and the intestines. This way we can virtually gain access to these organs that are long gone. Therefore, using DNA from dental calculus we get a glimpse of how health, disease and diet looked like prior to our industrialized lifestyle. We can then compare it to the white gooey stuff that we remove from people today and study the evolution of diet, health and disease. Because, by understanding our past, we will be able to better manage health in the future.

This study has the unique potential to explore and provide new insights in the results of human interaction, specifically human interaction in first encounter and colonization settings. In such interactions, the transmission and evolution of diseases fundamentally impact human population dynamics and their development over time. The effects of these impacts have hitherto been difficult to study using conventional anthropological techniques. The rapid development and application of biomolecular techniques has opened up a new world of opportunities. In addition, the use of archaeological dental calculus to investigate disease is a new and powerful technique in this innovative area of research.

By Kirsten Ziesemer